Compensation circuits are widely used to adjust a resistive load, for example in a differential amplifier, that sustains parameter changes due to integrated circuit operation and temperature variation. Typically, the compensation circuit uses a counter to vary the required compensation for the circuit. The compensation circuit monitors the resistive load and increments or decrements that counter whenever the resistive load falls outside a desired range. By appropriately incrementing or decrementing the counter, the resistive load can be adjusted back within the desired range.
Conventional compensation circuits allow the counter to continuously roll over if the resistive load could not be compensated within the desired range. This roll over effect by the counter would cause the compensation circuit to malfunction and endlessly count through the entire compensation range. Therefore, it is desirable to have a compensation circuit which prevents the counter from rolling over and causing a malfunction of the compensation circuit.
From the foregoing it may be appreciated that a need has arisen for a compensation circuit that does not malfunction when compensating an out of range resistive load. A need has also arisen for a compensation circuit that prevents a counter from endlessly rolling over in response to an out of range resistive load.